running ShapedClock example on Windows with raster engine works fine. But when i change the graphics system to raster on mac, the mask is ignored and the shaped clock is simply rectangular. Is this a bug? Or is there a Workaround?

running ShapedClock example on Windows with raster engine works fine. But when i change the graphics system to raster on mac, the mask is ignored and the shaped clock is simply rectangular. Is this a bug? Or is there a Workaround?